This eid is an ancient Persian holiday that was marked and celebrated before the emergence of Islam.
There is a hadith from Imam Sadeq (as) in hadith sources regarding Nowruz which the popular vote has verified it to be reliable and therefore they have given the fatwa to the fadhilah (recommendation) of ghusl (ritual washing) on the day of Nowruz, however some have objected and seen it to be unreliable.
Consequently, we cannot assure this eid to be a religious one, nevertheless we must note that there has been no objection presented against it in the ahadith. As a result, this event is categorized under the mubahaat (things that which are permissible) especially since this eid coincides with times that remind us of the greatness of the lord, the creator of nature and moreover, people perform rituals that are recommended is Islam, such as: cleaning the house, visiting relatives and family, celebration by the mu’mineen (believers), removing enmity and hatred between each other, freeing prisoners, etc. Furthermore, we know that Imam Ali (as) says that: Every day in which we do not disobey Allah, is an eid. Yes, there are a few traditions like jumping over fire and… that not only do we not have any Islamic proof for their legitimacy, we must actually try our best to put an end to them, for they are no more than superstition rather than being a part of religion.
Eid Nowruz is one of the holidays that Persian speaking countries like Iran and other neighboring countries celebrate along with Kurdish speaking people in Iraq, Turkey and Syria.
This eid is an ancient one, marked and celebrated before the emergence of Islam.
Among the references that we have available, we weren’t able to find a hadith or saying from a faqih regarding this holiday before Sheikh Tusi (460 H.), who has narrated a hadith in Misbah Al-Mutehajjid from Mu’alla bin Khanees, from Imam Sadeq (as): On the day of Nowruz do ghusl and put on your cleanest and purest clothing, use perfume and fast for the day. After praying the nawafil (extra recommended prayer) and dhuhr and asr prayers perform four raka’ts of prayer. In the first raka’t recite Surah Hamd once and Surah Al-Qadr ten times, in the second raka’t recite Surah Hamd once and Surah Al-Kaferun ten times, in the third raka’t recite Surah Hamd once and Surah Attawhid ten times and in the fourth raka’t recite Surah Hamd once and Surah Annas and Surah Al-falaq both ten times and after prayer go to sajdah and do shukr (thanks) to Allah and ask Him to forgive the sins of fifty years of your life.
Yet again, in Muhadhab, the same narrator narrates that Imam Sadeq (as) said: Nowruz is the same day that the Prophet (saw) got baya’t (allegiance) for Amir Al-Mu’mineen (as) on the day of Ghadir and everyone acknowledged his wilayah and those who remained loyal to it are blessed and those who broke it are doomed and it is also the same day the messenger of Allah (saw) sent Ali to the valley of jinn to get their pact and the day of his victory over the people of Nahrawaan and the day he killed Dhu-Thadiyyah. It is the day our Qaa’em (The Awaited One) of our progeny will emerge with his companions and may God defeat the Dajjal with his hands and hang him on the synagogues of Kufah. Nowruz never comes without us unless we anticipate relief and deliverance in it, because it originally belonged to us, but the Persians maintained it and you ruined it. (He then continued) a prophet from Bani Israel (the children of Israel) asked the Lord to revive thousands of people who had fled from their homes out of fear of death that had died, so God revealed to him to sprinkle water on them and that day he poured water on them and they amazingly came back to life; they were 30 thousand individuals, from that day on, sprinkling water became a tradition and only the knowledgeable are aware of its origin and that day was the first day of the Persian calendar. Mua’lla says: (The Imam (as)) dictated this to me and I wrote it down.
The majority of late faqihs have acted according to this hadith and therefore given the fatwa to the fadhilah (recommendation) of ghusl (ritual washing) on the day of Nowruz. The author of Jawaher states: the recommendation of ghusl on the day of Nowruz is popular among the late scholars based on the hadith of Mua’lla bin Khanees from Imam Sadeq (as) that has been narrated from Misbah, in addition to the fact that we have not seen any opposition to this issue.
However, the late Ayatullah Khu’i has not accepted the hadith since it is mursal (a hadith whose chain of transmitters lacks one or more narrators) and asserts that: The hadith of Mua’lla bin Khanees is mursal and therefore unacceptable unless one accepts the rule of Tasamuh fi Adillah al-Sunan which we don’t concede to.
Based on the above we cannot introduce this eid as a completely religious one.
Although, we must note the question that assuming that Allah has not introduced and announced this eid as an Islamic eid, has he forbidden us from celebrating it and considered it to be haram?
In response: Ibn Shahr ashub has mentioned a hadith in his book, Manaqeb that says: it has been narrated that Mansur Dawaneqi had sent a messenger to Imam Musa bin Ja’far (as) to ask him to be present in a ceremony and sit beside him while the people would bring gifts for the occasion of Nowruz. The Imam replied: I reviewed the ahadith of my forefather, the Messenger of Allah and didn’t find any hadith for this occasion, this is a Persian tradition that Islam has put an end to, and we seek refuge to Allah to revive something that has been diminished by Islam.
Mansur said: We merely celebrate this day as a political approach to keep our army content and I swear you to Allah to attend the ceremony and sit beside me. His holiness attended and the ministers, commanders, lieutenants and army men would bring gifts and greet them….
It is evident that the value of this hadith is weak and unacceptable because Ibn Shahr Ashub has not mentioned the chain of narrators and starts it with “و حکی (and he recounted)” and this proves it to be unreliable.
We must note that the issue of celebrating Eid Nowruz was a common and frequent matter that would have been explicitly mentioned and forbidden with emphasis by the imams (as) in the case of them not approving of it. Clearly, there would be mention of Nowruz in the presence of the imams, but they wouldn’t forbid it and count it as falsehood. Without doubt we cannot rely on a single hadith, given that it is also mursal, to eliminate a long known and well rooted tradition. Hence, this matter must be categorized among the mubahat (things that which are permissible) especially because this time coincides with the renewing days of nature’s astonishing beauty, God’s greatness and the reviving of life which is reminiscent of the resurrection. Moreover, on these days, people perform rituals that are religiously encouraged, such as: cleaning the house, visiting relatives and family, celebration by the mu’mineen (believers), removing enmity and hatred between each other, freeing prisoners, etc. Yes, there are a few traditions like jumping over fire that not only do we not have any Islamic proof of their legitimacy, we must actually try our best to abolish them for they are superstition (made up rituals that are not backed by religion) rather than acts of religion.
Regarding this issue, as a good ending for this article, Imam Ali (as) says that: Every day in which we do not disobey Allah, that day is eid.
 Wasa’el al-Shia, vol. 8, pg. 173.
 Jawahir al-Kalaam fi Sharh Shara’ye’ al-Islam, vol. 5, pg. 42; Al-Urwah al-Wuthqaa (annotated), vol. 2, pg. 152.
 Mowsu’ah Imam Khu’i, vol. 10, pg. 50.
 Al-Manaaqib, vol. 4, pg. 319.
 See: Kafi, vol. 5, pg. 142; Man Laa Yahduruhu al-Faqih, vol. 3 pg. 300.
 Nahjul-Balaghah, pg. 551, no. 428.